The purpose of this blog is to provide a brief resume of
the types of spectacle lenses available to the patient
for better vision (visual needs).
Here we can discuss and share all about ophthalmic lenses, theories, individual findings, inventions, optical standards, tolerance, errors, complex optics and more..

Thursday, July 24, 2014

Since a long time, optical labs are using adhesive block pads for holding the lens into the blocks for finished lens edging. There are various quality block pads are available in the market. Some of them are more adhesive some are less. Some are very difficult to remove from the lens after the edging, some are very easy but may rotate inside the edger which leads to wrong shape cutting or axis turn. Its always a headache for the technicians to stick with a same quality of block-pad for all the lenses types.Main disadvantages of finished block pads:

By increasing the clamp pressure to avoid slippage also can lead to coating defect.

Need to use additional protective pads for super hydrophobic lenses.

Unnecessary rejections

Higher cost depends on the pad's quality.

Block-lessAll the above mentioned problems will be eliminated by using the block less system. A block-less all-in-one finishing system is the sole economic solution for a lab because it eliminates expensive shortcomings of traditional edging technology. It operates with no blocks, no decentration device and no manual handling. Usually its working with vacuum system. Weco Edge 990, MEI TBA system for MEI641 and Bisphera, Schneider HSC Modulo are some of the edgers supports block-less edging.

Main Advantages

No labor costs

No job preparation

No stickers

No blockpads

No blocks

Simplified finishing process

No investment for separate blocking device

Savings in rejects

No time waste on putting pads on blocks and removing them

No more crazing defects caused by de-blocking the lens and slipping on the block

No more mis-loaded lenses due to lenses moving in the job tray from conveyor vibration, loader misalignment, decentered lenses.